The study aimed to evaluate and compare antioxidant activity couple with the phytochemical screening of different extracts from stems and flowers of Ageratum conyzoides. N-hexane, ethyl acetate, and ethanolic extracts were subjected to different phytochemical screening and antioxidant activity. The flavonoids and phenolic contents were determined using spectrophotometry method. The three extracts showed evidence for the presence of secondary metabolites such as flavonoids, steroids, terpenoids, and glycosides. Saponins were only present in ethanol extract. Phenol was present in both ethanol, ethyl acetate, and n-hexane extracts. The concentration of flavonoids ranges from 145.33 ± 0.665 to 711.00 ± 2.024 µg/g expressed as Quercetin equivalents. Total phenolic content expressed as Gallic acid equivalents range from 19.26 ± 0.305 to 150.33 ± 1.020 µg/g of extract. The DPPH inhibition was also determined using spectrophotometry method and it was observed between 34.65 to 84.90%. The results obtained in this study show that the stems and flowers of Ageratum conyzoides are rich in flavonoids and phenols. Thus, the plant possesses scavenging property.